Industrial, commercial, and residential use of water typically adulterates the water by addition of contaminating substances. In residential systems, a common adulterant is spent laundry detergent, which contains large amounts of sulfates. In commercial and industrial settings, water is used as a coolant, drainage agent, dilution compound, solvent, and the like. A particular use of water in some commercial environments involves power washing of objects such as sidewalks and buildings. Additionally, even if not involved directly in operations, water can become part of industrial settings as in mining where pools of water collect in shafts, abandoned mine tunnels, open mine strips, and similar features. These pools of water collect vast amounts of minerals and acids. A common issue with each area of use is the accumulation of hard water ions, e.g., divalent alkali metals. Water treatment can be costly and time consuming and does not always reduce contaminants in the water below a level such that the water is suitable for reuse.
Water also is used for stimulation of hydrocarbon and natural gas wells as well as in hydraulic fracturing. Recently, hydraulic fracturing has dramatically increased the amount of hydrocarbon production. Large volumes of fresh water injection coupled with water conservation efforts have increased an emphasis on oilfield water management such as water reuse. However, reuse of oilfield waste water poses a challenge to the industry.
Used oilfield water typically contains hydrogen sulfide. Removal of the hydrogen sulfide is warranted if the waste water is to be reused because hydrogen sulfide is corrosive, toxic, and flammable. Attempts to remove hydrogen sulfide from water include sulfide ion complexation, aeration, and stripping. If the water contains a precipitate, its reuse is limited because precipitates plug pore throats and damage formations.
The development of processes and systems that can be used to treat water and decrease hydrogen sulfide in the water is very desirable.